Insights into mountain river processes with topo-bathymetric LiDAR data

Abstract

Mountain rivers are characterised by irregular bedforms, shallow flow depths, spatially and temporally variable sediment availability, and high flow resistance due to boulder elements. So far, the full reproduction of Alpine river beds was limited to cross-sectional, punctual information. The progress in remote sensing technologies now enables area wide bathymetry surveys. Depending on the conditions, a water-penetrating laser of a topo-bathymetric LiDAR system delivers data with up to 50 survey points/m² when operated from a crewed aircraft. The data allows a detailed reproduction of the river bed and numerical investigations of hydraulic and morphological processes. This contribution provides first insights into a detailed reproduction of the river bed based on topo-bathymetric LiDAR data and its influences on flow property results of a hydrodynamic numerical model for the mountain river section Passer in South Tyrol (Italy).